The present invention relates to an apparatus for operating a throttle valve.
In passenger cars, with the development and use of autocruise devices, driving force control devices, idle control devices and the like, the necessity of electrically controlling the degree of opening of a throttle valve has increased. In the past, the throttle valve and an accelerator pedal were mechanically connected by a wire or the like so that when the vehicle was being normally driven, the degree of opening of the throttle was mechanically controlled by the accelerator pedal, and when necessary, the degree of opening of the throttle was controlled by an electric motor or a vacuum servo device.
However, if the amount that the accelerator pedal is depressed is electrically detected and the throttle valve is electrically operated according to the detected amount, more accurate control can be obtained, which is rational. Such system as just mentioned has been already proposed. However, in this proposal in which the degree of opening of the throttle is always electrically controlled, if any special back-up mechanism is not provided, the control of the degree of opening of the throttle would be rendered impossible at the time of occurrence of an electric failure.